Developing a Precautionary Management Approach for the Eastern Canada-West Greenland Population of Bowhead Whales (Balaena mysticetus)

Ferguson, Steven H.; Higdon, Jeff W.; Hall, Patricia A.; Hansen, Rikke G.; Doniol‐Valcroze, Thomas

doi:10.3389/fmars.2021.709989

Cited by 14 publications

(11 citation statements)

References 64 publications

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“…The presence of bowhead whale DNA deep in the Nuuk fjord at the two sites, Iffiartarfik and Qoornoq (dated to AD ~1500-1800), raises questions about the former range of this species. The modern range of bowhead whales does not extend as far south as the Nuuk area 41 , but records from the mid 1800’s suggest that it did sporadically in the past 42 . However, it is also possible that the presence of bowhead whale DNA at Iffiartarfik and Qoornoq is the result of trading, either with other Inuit or with European whalers who started operating in the area in larger numbers in the early 18 th century 43 .…”

Section: Resultsmentioning

confidence: 99%

New insights into 4,000 years of resource economy across Greenland using ancient DNA

Seersholm

Harmsen

Gotfredsen

et al. 2022

Preprint

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The success and failure of past cultures across the Arctic was tightly coupled to the ability of past people to exploit the full range of resources available to them, and to adapt to fluctuations in resource availability. There is substantial evidence for the hunting of birds, caribou and a wide range of marine mammals in pre-historic Greenland from bone remains preserved in ancient middens. However, the extent to which these communities relied on marine resources such as fish and large cetaceans is understudied because of the taphonomic processes and bias that affect how these taxa present themselves in the archaeological record. To address this, we analyse DNA from bulk bone samples from 12 archaeological sites across Greenland dating from Paleo-Inuit to Neo-Inuit periods. Using a combination of metabarcoding and shotgun metagenomics we identify an assemblage of 43 species consisting of birds, fish, and both marine and terrestrial mammals. We find genetic evidence of five different whale species, of which the bowhead whale (Balaena mysticetus) was the most commonly detected. Furthermore, we detect nine fish species, of which four have not previously been identified in any of the studied sites. Lastly, we identify a novel haplotype in caribou (Rangifer tarandus) at the 3,000-year-old site Itinnera, suggesting the presence of a distinct lineage of (now extinct) dwarfed caribou that colonised Greenland after the last ice age 9,000 years ago. Collectively, these findings provide a rare insight into whaling and fishing practices in Greenland and demonstrate that prehistoric Greenlandic communities had the social and technological capacity to target the largest whales available in the waters around them.

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Section: Resultsmentioning

confidence: 99%

New insights into 4,000 years of resource economy across Greenland using ancient DNA

Seersholm

Harmsen

Gotfredsen

et al. 2022

Preprint

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“…These unavoidable limitations in study design reflect logistical constraints of studying mysticete whales. Baleen cannot be collected from living whales, and as stranded bowhead carcasses are exceedingly rare and logistically challenging to necropsy, samples are limited to baleen collected from indigenous hunts; but few bowheads are harvested per year and large adults are rarely harvested ( Ferguson et al. 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes

Hunt

Buck

Ferguson

et al. 2022

Integrative Organismal Biology

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Synopsis Male mammals of seasonally reproducing species typically have annual testosterone (T) cycles, with T usually peaking during the breeding season, but occurrence of such cycles in male mysticete whales has been difficult to confirm. Baleen, a keratinized filter-feeding apparatus of mysticetes, incorporates hormones as it grows, such that a single baleen plate can record years of endocrine history with sufficient temporal resolution to discern seasonal patterns. We analyzed patterns of T every 2 cm across the full length of baleen plates from nine male bowhead whales (Balaena mysticetus) to investigate occurrence and regularity of T cycles and potential inferences about timing of breeding season, sexual maturation, and reproductive senescence. Baleen specimens ranged from 181–330 cm in length, representing an estimated 11 years (smallest whale) to 22 years (largest whale) of continuous baleen growth, as indicated by annual cycles in stable isotopes. All baleen specimens contained regularly spaced areas of high T content (T peaks) confirmed by time series analysis to be cyclic, with periods matching annual stable isotope cycles of the same individuals. In 8 of the 9 whales, T peaks preceded putative summer isotope peaks by a mean of 2.8 months, suggesting a mating season in late winter / early spring. The only exception to this pattern was the smallest and youngest male, which had T peaks synchronous with isotope peaks. This smallest, youngest whale also did not have T peaks in the first half of the plate, suggesting initiation of T cycling during the period of baleen growth. Linear mixed effect models suggest that whale age influences T concentrations, with the two largest and oldest males exhibiting a dramatic decline in T peak concentration across the period of baleen growth. Overall, these patterns are consistent with onset of sexual maturity in younger males and possible reproductive senescence in older males. We conclude that adult male bowheads undergo annual T cycles, and that analyses of T in baleen may enable investigation of reproductive seasonality, timing of the breeding season, and life history of male whales.

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“…However, to what extent the carrying capacity of high-latitude ecosystems will be able to support a greater population of whales is unknown. Furthermore, population models suggest that the EC-WG bowhead whale population rebounded following commercial exploitation by whaling in the early 1900s more slowly than would be predicted based on demographic expectations (Ferguson et al, 2021). Delayed recovery may indicate that the marine ecosystem was degraded from over exploitation and the population will be unable to recover to preexploitation stock sizes or pristine carrying capacity (Savoca et al, 2021).…”

Section: Sensitivity To Climate Changementioning

confidence: 99%

Year-round foraging across large spatial scales suggest that bowhead whales have the potential to adapt to climate change

Fortune

Trites²,

LeMay³

et al. 2023

Front. Mar. Sci.

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The ecological impact of environmental changes at high latitudes (e.g., increasing temperature, and decreased sea ice cover) on low-trophic species, such as bowhead whales, are poorly understood. Key to understanding the vulnerability of zooplanktivorous predators to climatic shifts in prey is knowing whether they can make behavioural or distributional adjustments to maintain sufficient prey acquisition rates. However, little is known about how foraging behaviour and associated environmental conditions fluctuate over space and time. We collected long-term movement (average satellite transmission days were 397 (± 204 SD) in 2012 and 484 (± 245 SD) in 2013) and dive behaviour data for 25 bowhead whales (Balaena mysticetus) equipped with time-depth telemetry tags, and used hierarchical switching-state-space models to quantify their movements and behaviours (resident and transit). We examined trends in inferred two-dimensional foraging behaviours based on dive shape of Eastern Canada-West Greenland bowhead whales in relation to season and sea ice, as well as animal sex and age via size. We found no differences with regards to whale sex and size, but we did find evidence that subsurface foraging occurs year-round, with peak foraging occurring in fall (7.3 hrs d-1 ± 5.70 SD; October) and reduced feeding during spring (2.7 hrs d-1 ± 2.55 SD; May). Although sea ice cover is lowest during summer foraging, whales selected areas with 65% (± 36.1 SD) sea ice cover. During winter, bowheads occurred in areas with 90% (± 15.5 SD) ice cover, providing some open water for breathing. The depth of probable foraging varied across seasons with animals conducting epipelagic foraging dives (< 200 m) during spring and summer, and deeper mesopelagic dives (> 400 m) during fall and winter that approached the sea bottom, following the seasonal vertical migration of lipid-rich zooplankton. Our findings suggest that, compared to related species (e.g., right whales), bowheads forage at relatively low rates and over a large geographic area throughout the year. This suggests that bowhead whales have the potential to adjust their behaviours (e.g., increased time allocated to feeding) and shift their distributions (e.g., occupy higher latitude foraging grounds) to adapt to climate-change induced environmental conditions. However, the extent to which energetic consumption may vary seasonally is yet to be determined.

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Developing a Precautionary Management Approach for the Eastern Canada-West Greenland Population of Bowhead Whales (Balaena mysticetus)

Cited by 14 publications

References 64 publications

New insights into 4,000 years of resource economy across Greenland using ancient DNA

New insights into 4,000 years of resource economy across Greenland using ancient DNA

Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes

Year-round foraging across large spatial scales suggest that bowhead whales have the potential to adapt to climate change

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